Prevention of +Gz-induced loss of consciousness

Objective recordings of respiratory and cardiovascular parameters at heart and head levels on human centrifuges and in flight provided the physiologic insights which led to development, during and shortly after World War II, of very effective anti-G suits and simultaneous use of positive pressure respiratory straining maneuvers. The high sustained Gz capabilities of current and future fighter planes have forced recourse to these techniques with minimal awareness of their origins. Possible catastrophic limitations of very effective full coverage anti-G suits, including water immersion to the apex of the thorax, especially when used without positive pressure breathing, were also documented at that time.